tomashek



Sept. 1933- w. M. TOMASHEK Re. 18,935

BURR PLATE Original Filed Aug. 15, 1929 2 Sheets-Sheet l Sept. 5, 1933- w. M. TOMASHEK BURR PLATE Original Filed Aug. 15 1929 2 Sheets-Sheet 2 William/ll Ends/Eek Q W7 M 81cm wa t Reissuecl Sept. 5,.1933

UNITED STATES PATENT oFFIcE Original No. 1,782,372, dated November 18, 1930, 4 Serial No. 386,030, August 15, 1929. Application for reissue 643,117

8 Claims.

' The invention relates to burr plates and has as an object the provision of a plate which'will grind grain to a uniform fineness.

It is a further object of the inventionto provide a burr plate which will grind grain with less expenditure of power than plates heretofore known. g

It is a further object of the invention to provide a burr plate which will grind grain without heating the same.

It is a further object of the invention to provide a plate made up of sections which may be assembled upon a support for use.

' It is a further object of the invention to provide a plate made up of sections so formed as to strengthen the portions necessary for greatest strength with the least material.

Further objects of the invention will appear from the following description when read in connection with the accompanying drawings, showing an illustrative embodiment of the invention and wherein: W

Fig. 1 is an elevation of an assembled plate;

Fig. 2 is a rear elevation of one section on an enlarged scale;

Fig. 3 is a front-elevation of onesection;

Fig. 4 is'an inside edge view of one section; and

Figs. 5, 6, and '7 are sections taken upon the corresponding lines of Fig. 3. I

As shown the assembled plate comprises an annular plate 10 made up of a plurality of like sections 11 as illustrated in Figs. 2 to 7 inclusive. As there shown each section comprises a plate which is a segment of the annulus and presents a front or working surface 12 and a rear surface 13. The sections are designed to be assembled upon a disc or annular support and to be secured thereto by bolts, the heads of which will be received in the tapered openings 14, which bolts will clamp the sections upon the support.

It is to be understood that the said supports will be revolved in opposite directions or one support will be revolved while the other support may be held stationary, two of the assembled annuli 10 being placed in opposed relation and separated to a distance corresponding to the fineness of the product desired, in the manner well understood in the art.

To contact with the support, there is shown a peripheral flange 15 and an inner flange 16 projecting rearwardly from the rear surface of the plate.

H To prevent the attaching bolts from deforming the plate, there are shownlugs 17 adjacent the November 17, 1932. Serial No.

bolt holes 14 which will receive the strain upon the plates as the bolts are tightened- For the purpose of balancing the assembled annulus into dynamic balance, the rear surface of the plate is shown as provided with cavities 18 and when the plates are assembled in the balancing of the assembly additional material may be drilled out of the cavities for the purpose of removing or adding weight as needed. For the purpose of retaining lead in the cavities, the cavities are preferably made of a dovetail cross section'as indicated at 19 in Fig. 5.

The front or working surface of each of sections 12 is. shown as formed with a peripheral flange 20 standing above said working surface and with a plurality of radial ribs 21 rising from the surface into the plane of the edge of the peripheral iiange 20 and the outer portion of said working surface, of the flange 20 and of the ribs 21, are in planes normal to the axis of the annulus, whereas the inner margin of the working surface from substantially the circumferential line 22 is sloped away from the plane normal to the axis of the'annulus, as clearly indicated inv Figs. 4 to 'Tinclusive. V

The surface of the ribs 21 is substantially parallel with the working surface.

Y The ribs 21 are shown'as'terminating short of the inner edge of the sections. Interspersed with the ribs 21, there are shown a plurality of ribs 23 which extend to the inner edge of the section and are circumferentially widened at their inner ends as indicatedat 24 for the purpose of feeding a'boss 25 placed between adjacent widened portions 24'and ribs 23 which is shown as rising to a less height than said widened portions 24, which boss may or may not be exactly in alignment with one of the ribs 21 and is not necessarily centrally placed between the widened portions 24 of the ribs 23.

' To control the progress of the feed to the outer periphery of the annulus, there are shown circumferential ribs 26 extending between the ribs 21 and 23, three of such ribs being shown, which ribs rise to a less height than the radial ribs 21 and 23 from the working surface.

By virtue of the presence of the ribs 26 feed will be checked in its outward movement and will be more thoroughly subjected tothe shearing action of the relatively oppositely moving radial ribs upon the opposed annuli. The ribs 26 are shownas sloping upwardly from their bases to their apices for better passage of thematerial thereover and toeliminate crevices and"corne'rs in which material would otherwise tend to lodge.

The working surface 12 is shown as sloping out.-.

wardly and upwardly to the surface of the peripheral flange 20 also to prevent lodging and for the better passage of material to discharge. It is understood that material will be fed through one of the Opposed annuli and between thesame to the working surfaces where it will be comminuted and will be discharged radially of the plates at the periphery thereof between the flanges 20. z

Since the annulus 10 is made up of sections and since at least one of the annuli as placed in the mill will be revolved at a high rate of speed, the centrifugal strain upon the plates must be resisted bygreater strength at the ends of the sec-.- tions than at the'centers, which ends'ar'e unsup ported since they are not integral with the endof the adjacent section. 'It .is, however, advanthe opposed edges of tageous to' construct the edge of the flange 20 as' thin as iscons'istent with'the necessary strength in order to reduce friction of the discharging ground product to reduce heating thereof, and to conserve energy. To meet these requirements, the ends '27 of'the peripheral flange 20 as well as of thesrearwardly' projecting peripheral flange '15 are made thicker thanthe centers thereof, as clearly shown .inFigs, '2 and '3.

. To better preserve dynamic balance, the difference in thickness o fthe peripheral flanges 15 and 20 'is compensatedforby thickening the inner flange 16 at the center portion upon each section, as clearly indicatedin Fig. 2. 1

e-For convenience in fitting the sections together at their ends, they are shown as formed with projecting portions 28,29, 30, the] surfaces of which may be ground to cause the assembled platesto accurately fit into a true annulus. .The endsofgribs 21 are shown as sloping outwardly away from the working surface l-2 as at 31 and the inner ends of the widened portions 24 of ribs 23 are shown rounded as at 32, all for the purposeofyfacilitating a uniform and even flow of grain-through the burrs. It is found-that attentionto each of the deof the plate as described results inthe pro'-, duction of an attrition. burr which will grind a considerable greater percentage of grain with the same'power than any plate which applicantin a iong experience has known and that the ground material leaving the platev is heated" very little and to a markedly less extent than 'is' the case with former knownmills. The heat which has,

formerly been produced in the grinding "of material is obviously a wasteof energy. as well as being in many injurious. to the material. In addition to the named advantage the pnoduc't ground by. the plates of the invention is of arm-m lineness, being devoid of any considerable portion of powder.

Minor changes may be madein the physical embodiment of the invention within the scope of the appended claims without departing from the-spirit ofthe invention.

I clairnz' i I 1. A burr plate comprising an annular member comprising a'plurality of radially separate sections, each section formed with a peripheral flange relatively thin at the center of thecircumferential extent of the section and thickened at the ends thereof, the working surface of the section sloping outwardly to the edge of the flange, a

plurality of relatively closely spaced radial ribs said inner edge and widened at their inner ends and a plurality of circumferential ribs extending between said radial ribs and of less height than the radial ribs.

2. A burr plate comprising an annular plate comprising a plurality of radially separate sections, each section" formed with a peripheral flange relatively thin at the central portion of the circumferentialextent of the section and ,widened atthe ends: thereof, the working surface of-the section sloping outwardly adjacent the flange to the edge thereof, the central and outer portions of the working surface of the said section radially thereof lying in a plane normal to'th'e axis .of the-annulus andtheinnerportion sloping away from said plane a-plurality ofgraa dial ribs rising above said working surface flush withsaidflange, certain of said ribs terminating short ofthe inner edge of thesection and others thereof interspersed with said certainribs exfoo tending to said inner edge, said extendedribs widened-at their'inner ends circumferentially of the section, the-free edges of said workingsuv;

face and a plurality of circumferential ribsex: tending betweenand of less height than said radial ribsQ, a q 3. A burr plate comprising anannular comprising a plurality-ofradially separate sections assembled on a revoluble support, each section formed with aperipheral flange projecting from the working-andfrorn the rear surface of;

the section, said flange being relativelyethin xat the center circumferentially ,ofthe section and' thickened at the ends thereof, also fflrmedwith a flange at its" inner edge extending above its rear surface, said last named flangethickened at its central portion andnwith bolt receiving openings and a lug adjacent each opening rising to the plane of the rearedge of said flanges, aplurality of radial ribs rising from the workingsurfacegof each section flush with the edge of said peripheral flange, certain of said ribs term-inating short of the inner edge of thesection and others of said ribsinterspersed with said tain ribs extending to said inner edge and circumferentially widenedadjacent said edge.

. 4. A burr plate comprising a series of segments mounted end to end in annular formation upon a revoluble support, said segments each having an outer flange heavier-1 towardits ends thanat its intermediate portion, and grinding ribs extending from the workingsurface of the-segment.

5. A burr plate-comprising a series of mounted end to end inannular formation upon a revoluble. support, said segments each having an outer flange heavier toward. its ends than at its intermediate portion,and grinding ribs extendi-ng from the working surface of the said segments having spaced end lugs to be machined for abutting contact to permit accurate fitting of, the; segments into :atriue annulusI V I f 6. A burr plate comprising an annular member formed of a plurality of radially -,separa ted sections having grinding faces on one side and assembled on a revolvable -support,r achfsection having an integral peripheral face flangefad jacent its outer edge andan integralreinforcing flange adjacent its inner, edge, a plurality of radial'ribs on the face of each section and terminating at their outer ends flush with said peripheral face flange, and a plurality of other ribs connecting theradial ribs and of less height than the latter, and certain of said radial ribs having circumferentially widened inner ends, said peripheral face flange of each section being narrower at its intermediate portion than toward its ends.

'7. A burr plate comprising a series of segments mounted end to end in annular formation upon a revoluble support, said segments each having an outer flange heaviertoward its ends than at its intermediate portion, and grinding ribs extending radially inwardly from said flange, means for retarding the flow of material to be ground outwardly between said radial ribs, certain of said ribs being longer than others and having their inner ends widened, the surface of the segment intermediate said widened ribs being sloped back from the plane of the surface proper.

, 8. A burr plate comprising an annular member comprising a plurality of radially separate sections assembled on a revoluble support, each section formed with arperipheral flange projecting from the working and from the rear surface of the section, said flange being relatively thin at the center circumferentially of the section and thickened at the ends thereof, also formed with a flange at its inner edge extending above its rear surface, a plurality of radial ribs rising from the working surface of each section flush with the edge of said peripheral flange, certain of said ribs terminating short of the inner edge of the section and others of said ribs intespersed with said certain ribs extending to said inner edge and circumferentially widened adjacent said edge.

WILLIAM M. TOMASHEK. 

